Himanshu Wadhwa, Joanne L. Sims, Rachael L. Niedere

Aim: To examine the rate of recurrence of toxoplasmosis retinochoroiditis within a New Zealand population and to examine risk factors for recurrence.

Methods: Retrospective observational case series of all subjects with toxoplasmosis retinochoroiditis presenting to Auckland District Health Board Department of Oph- thalmology between 2006 – 2019.

Results: A total of 115 subjects were included with a median age at initial diagnosis of 36.7 years (interquartile range 23.7 to 53.8). 16 subjects (13.9%) were immunosuppressed. 30.2% (26 subjects out of the 82 subjects who had serology performed) were IgM-positive at presentation. Mean follow up was 6.1 years per person. Seventy- three recurrences occurred during follow up in 36 subjects (31.3%). 88.4% of cases were treated with oral antibiotics. After treatment, most immunosuppressed subjects also received prophylactic antibiotics. Recurrence occurred in 14.8% in the first year (95% confidence interval 10.3% – 21.0%) and risk of recurrence was increased by 2x for every previous documented recurrence (p < 0.001). There was no statistically significant increased risk of recurrence with age, IgM-positivity, macular involvement or immunosuppression. Conclusions: Toxoplasmosis had a 14.8% risk of recurrence in the first year, with each previous recurrence increasing the risk by 2x.